环境准备

5 个 Istio 访问外部服务的流量控制常用例子,强烈建议收藏起来,以备不时之需。

部署 sleep 服务,作为发送请求的测试源:

kubectl apply -f samples/sleep/sleep.yaml

在 Istio 外部,使用 Nginx 搭建 duckling 服务的v1和v2两个版本,访问时显示简单的文本:

> curl -s http://192.168.1.118/
This is the v1 version of duckling.
> curl -s http://192.168.1.119/
This is the v2 version of duckling.

访问外部服务

执行如下命名访问外部服务 httpbin.org :

export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- curl -s http://httpbin.org/headers

返回结果如下:

{
  "headers": {
    "Accept": "*/*", 
    "Host": "httpbin.org", 
    "User-Agent": "curl/7.81.0-DEV", 
    "X-Amzn-Trace-Id": "Root=1-62bbfa10-3237e3b9662c65ae005148ab", 
    "X-B3-Sampled": "0", 
    "X-B3-Spanid": "9e650093bf7ae862", 
    "X-B3-Traceid": "1da46d7fafa5d71c9e650093bf7ae862", 
    "X-Envoy-Attempt-Count": "1", 
    "X-Envoy-Peer-Metadata": "......", 
    "X-Envoy-Peer-Metadata-Id": "sidecar~......"
  }
}

此时的方法,没有通过Service Entry,没有 Istio 的流量监控和控制特性。创建 Service Entry :

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: httpbin-ext
spec:
  hosts:
  - httpbin.org
  ports:
  - number: 80
    name: http
    protocol: HTTP
  resolution: DNS
  location: MESH_EXTERNAL
EOF

再此次访问,返回结果如下:

{
  "headers": {
    "Accept": "*/*", 
    "Host": "httpbin.org", 
    "User-Agent": "curl/7.81.0-DEV", 
    "X-Amzn-Trace-Id": "Root=1-62bbfbd6-254b05344b3cde2c0c41b3b8", 
    "X-B3-Sampled": "0", 
    "X-B3-Spanid": "307c0b106c8b262e", 
    "X-B3-Traceid": "f684a50776c088ac307c0b106c8b262e", 
    "X-Envoy-Attempt-Count": "1", 
    "X-Envoy-Decorator-Operation": "httpbin.org:80/*", 
    "X-Envoy-Peer-Metadata": "......", 
    "X-Envoy-Peer-Metadata-Id": "sidecar~......"
  }
}

可以发现由 Istio 边车添加的请求头:X-Envoy-Decorator-Operation

设置请求超时

向外部服务 httpbin.org 的 /delay 发出请求:

export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- time curl -o /dev/null -sS -w "%{http_code}\n" http://httpbin.org/delay/5

返回结果如下:

200
real    0m 5.69s
user    0m 0.00s
sys     0m 0.00s

请求大约在 5 秒后返回 200 (OK)。

创建虚拟服务,访问外部服务 httpbin.org 时, 请求超时设置为 3 秒:

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: httpbin-ext
spec:
  hosts:
    - httpbin.org
  http:
  - timeout: 3s
    route:
      - destination:
          host: httpbin.org
        weight: 100
EOF

再此次访问,返回结果如下:

504
real    0m 3.01s
user    0m 0.00s
sys     0m 0.00s

可以看出,在 3 秒后出现了 504 (Gateway Timeout)。 Istio 在 3 秒后切断了响应时间为 5 秒的 httpbin.org 服务。

注入 HTTP 延迟故障

向外部服务 httpbin.org 的 /get 发出请求:

export SLEEP_POD=$(kubectl get pods  -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- time curl -o /dev/null -sS -w "%{http_code}\n" http://httpbin.org/get

返回结果如下:

200
real  0m 0.45s
user  0m 0.00s
sys 0m 0.00s

请求不到 1 秒就返回 200 (OK)。

创建虚拟服务,访问外部服务 httpbin.org 时, 注入一个 3 秒的延迟:

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: httpbin-ext
spec:
  hosts:
    - httpbin.org
  http:
    - fault:
        delay:
          fixedDelay: 3s
          percentage:
            value: 100
      route:
        - destination:
            host: httpbin.org
EOF

再此次访问 httpbin.org 的 /get ,返回结果如下:

200
real  0m 3.43s
user  0m 0.00s
sys 0m 0.00s

可以看出,在 3 秒后出现了 200 (OK)。

流量转移

访问duckling服务时,所有流量都路由到v1版本,具体配置如下:

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: duckling
spec:
  hosts:
  - duckling.com
  ports:
  - number: 80
    name: http
    protocol: HTTP
  location: MESH_EXTERNAL
  resolution: STATIC
  endpoints:
  - address: 172.24.29.118
    ports:
      http: 80
    labels:
      version: v1
  - address: 172.24.29.119
    ports:
      http: 80
    labels:
      version: v2
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: duckling
spec:
  hosts:
  - duckling.com
  http:
  - route:
    - destination:
        host: duckling.com
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: duckling
spec:
  host: duckling.com
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
EOF

执行如下命名访问外部服务 duckling.com :

export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- curl -s http://duckling.com/

多次访问后,返回结果一直是:This is the v1 version of duckling.

访问duckling服务时,把50%流量转移到v2版本,具体配置如下:

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: duckling
spec:
  hosts:
  - duckling.com
  http:
  - route:
    - destination:
        host: duckling.com
        subset: v1
      weight: 50
    - destination:
        host: duckling.com
        subset: v2
      weight: 50
EOF

多次访问外部服务 duckling.com ,有时返回This is the v1 version of duckling.,有时返回This is the v2 version of duckling.

访问duckling服务时,所有流量都路由到v2版本,具体配置如下:

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: duckling
spec:
  hosts:
  - duckling.com
  http:
  - route:
    - destination:
        host: duckling.com
        subset: v2
EOF

多次访问外部服务 duckling.com ,一直返回This is the v2 version of duckling.

基于请求头的路由

请求头end-user为OneMore的所有流量都路由到v2版本,其他流量都路由到v1版本,具体配置如下:

kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: duckling
spec:
  hosts:
  - duckling.com
  ports:
  - number: 80
    name: http
    protocol: HTTP
  location: MESH_EXTERNAL
  resolution: STATIC
  endpoints:
  - address: 172.24.29.118
    ports:
      http: 80
    labels:
      version: v1
  - address: 172.24.29.119
    ports:
      http: 80
    labels:
      version: v2
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: duckling
spec:
  hosts:
  - duckling.com
  http:
  - match:
    - headers:
        end-user:
          exact: OneMore
    route:
    - destination:
        host: duckling.com
        subset: v2
  - route:
    - destination:
        host: duckling.com
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: duckling
spec:
  host: duckling.com
  subsets:
    - labels:
        version: v1
      name: v1
    - labels:
        version: v2
      name: v2
EOF

执行如下命名访问外部服务 duckling.com :

export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- curl -s http://duckling.com/

多次访问的返回结果一直是:This is the v1 version of duckling.

设置请求头end-user为OneMore,访问外部服务 duckling.com :

kubectl exec "$SLEEP_POD" -c sleep -- curl -H "end-user:OneMore" -s http://duckling.com/

多次访问的返回结果一直是:This is the v2 version of duckling.

以上就是5个 Istio 访问外部服务流量控制最常用的例子的详细内容,更多关于Istio 访问外部服务流量控制的资料请关注本站其它相关文章!

点赞(0) 打赏

评论列表 共有 0 条评论

暂无评论

微信公众账号

微信扫一扫加关注

发表
评论
返回
顶部